The present invention relates to a three component polymer blend having good mechanical properties and flame retardancy for use in making molded parts.
Impact resistant, weatherable polymer compositions comprising acrylate, styrene, and acrylonitrile components are known. U.S. Pat. No. 3,944,631 to A. J. Yu et al., which discloses one of the components used in the blends of the present invention, describes an interpolymer comprising: (a) crosslinked (meth)acrylate; (b) crosslinked styrene-acrylonitrile; and (c) uncrosslinked styrene-acrylonitrile polymeric components. This material is said to have superior weather resistance as compared to ABS polymers and is only taught in U.S. Pat. No. 3,944,631 for use by itself without blending with other polymeric materials.
Blends of the polymer composition described in U.S. Pat. No. 3,944,631 with certain specific thermoplastic polymers are also described in the literature. For example, U.S. Pat. No. 4,168,285 to M. J. Turczyk describes blends of vinyl chloride polymer and the polymer composition shown in U.S. Pat. No. 3,944,631. Also, blends of acrylic polymers with this composition are described in pending U.S. Ser. No. 176,887, filed Aug. 11, 1980.
Three component blends which comprise the composition of U.S. Pat. No. 3,944,631 are described in U.S. Pat. No. 4,160,793 to P. Kraft et al. in which the other two components are vinyl chloride polymer and chlorinated vinyl chloride polymer.